Thermal performance is a critical issue for the lifetime of light emitting diode, LED, based lighting devices. LEDs normally generate a majority of the heat in a lighting device, while the driver (for electrically driving the LEDs) only generates a small part of the heat. The LEDs can withstand relatively high temperatures compared to the driver, in which some components are sensitive to high temperatures and degrade in time if exposed to heat. However, in current LED-based lighting devices, the LEDs and the driver are normally arranged in proximity to each other and in connection to the same heat sink. As heat generated by the LEDs adversely affects the driver, high demands are put on heat dissipation from the driver for obtaining acceptable lifetimes of such lighting devices. For enhancing heat dissipation, the driver is normally fixed in a cavity of the heat sink by thermal glue (or thermal potting material), which however is expensive and makes assembly as well as recycling more cumbersome.
WO 2011042357 shows a lighting device having a heat sink arranged in the top, an LED mounted to the lower side of the heat sink, and a cavity for the driver arranged in the lower portion of the lighting device. A tapered reflector extends from the lower portion up to the heat sink and encloses a wire connecting the LED with the driver.